M̃
M̃ is a Latin M with a diacritical tilde.Linguistic use
M̃–m̃ is or was used as a grapheme in several languages:
In Italian, the abbreviation Ssm̃o or SSm̃o may be used for Santissimo, "most holy".M̃ and m̃ are used in mathematics and physics, see Tilde#Mathematics and Tilde#PhysicsComputer use
On the Apple ABC extended keyboard, m̃ is made by typing m and then option-shift n.